Can I stay in Thailand until January with a 6-month multiple entry visa without going to immigration after 60 days?

If you enter Thailand with a 6-month multiple entry tourist visa, you'll initially receive a 60-day stay stamp. As you approach the end of this 60-day period, you can either apply for a one-time 30-day extension at immigration or exit Thailand and re-enter to get a new 60-day stamp. Your visa's overall validity for 6 months does not affect the maximum continuous stay allowed, which typically caps at 60-90 days without leaving the country. By properly timing your extensions and re-entries, you can maximize your stay.